Many methods have been proposed in the prior art for randomly or selectively producing chlorinated hydrocarbons from hydrocarbons and/or chlorohydrocarbons in processes involving modified Deacon-type chlorination procedures. In processes of this character, oxygen, the hydrocarbon and/or chlorohydrocarbon to be chlorinated, and chlorine or HCl as the chlorinating agent, are brought into contact at elevated temperatures with a metal halide catalyst, usually a copper chloride-containing catalyst. Where HCl is utilized as the feed material, it is believed that a preliminary oxidation of the HCl takes place resulting in the formation of water and elemental chlorine. The chlorine produced then reacts with the hydrocarbon and/or chlorohydrocarbon feed to produce further quantities of HCl and a chlorinated derivative of the feed material. When chlorine is utilized as the chlorinating agent, it is believed that an initial chlorination of the hydrocarbon and/or chlorohydrocarbon takes place which generates HCl. The HCl thus generated is converted by the conventional Deacon reaction to chlorine and water.
In recent years considerable emphasis has been laid on fluid bed processes for conducting such oxychlorination procedures since the reactions involved are highly exothermic and the removal of heat usually becomes a problem of considerable moment. In conducting fluidized bed oxychlorination procedures of this type, however, many difficulties are encountered. For example, in some instances the fluidized bed does not provide sufficient contact with the initial feed to produce complete chlorination or high yields of substitutive chlorination. Also, the fluidized bed becomes hard to handle in high temperature chlorination procedures. Consequently, many methods have been devised for providing adequate cooling of the fluidized bed catalyst particles employed during reaction. Various carriers have been tested to determine the best materials from the standpoint of thermal conductivity, lack of attrition during fluidization, and other similar considerations in order to arrive at a material suitable for use as a support for the catalyst material employed during the chlorination reaction. Product recovery from the reaction zones without injuring the catalyst particles is also another problem encountered in this area. Many of the gas mixtures fed are highly explosive under certain conditions so that proper mixing of them is an extremely important factor. In addition, corrosion of materials of construction utilized in forming the reactors involved, and the selection of the proper size of the reactors for the purpose of providing maximum productivity are also problems. It has also been found that when conducting these processes in large reactors (two feet or more in diameter), a considerable sacrifice in overall efficiency of the process contemplated is experienced.
The commercial success of these processes is due largely to the demand for halogenated compounds containing from 1 to 10 carbon atoms; however, there is a great need for improvement of these processes. For example, it would be highly desirable to reduce the contact time normally associated with fixed bed operations, while eliminating the difficulties associated with fluidized solids operation such as catalyst attrition and catalyst vaporization which appears to be more pronounced with highly active catalysts. While the moving bed solves some of these difficulties, it is not without its own particular problems such as those derived from the mechanical transportation of catalysts throughout a zone and the existence of "hot spots" in the catalyst bed. The heat of reaction generated on the surface of the solid permits direct oxidation of the hydrocarbon and/or chlorohydrocarbon to produce undesirable oxides of carbon.
The more active metal halide catalysts such as, copper chloride, are more volatile at required halogenation temperatures and thus, it is difficult to retain the catalyst in the system and maintain the activity of the catalyst mass over an extended period of time. In such systems the volatilized catalyst must be recovered by condensation or other troublesome methods and returned in a supported state to the reaction zone. Thus, the economics of operating with fluidized catalysts is poor in spite of the fact that such a system provides better temperature control and higher yield of product for a given period of operation.
Therefore, it is readily apparent that a new chlorination process is needed with overcomes the above difficulties by providing a more economic and commercially feasible chlorination process. Additionally, a better chlorination process is desired to provide improved contact between the hydrocarbon and/or chlorohydrocarbon and chlorinating agents in conjunction with good temperature control of the reaction zone. Furthermore, a selective chlorination process (i.e., a process that produces predominantly one specific chlorinated product in high yields) is in great demand throughout the industry.